A dispersion unit has a mouth-piece (10) in which an annular channel (12) is provided for supplying a particle flow and has an axial inlet (14) and an axial outlet (16) in which an annular guide chamber (18) is joined to the outlet and in which the axially entering particle flow is guided into a mainly radial direction of flow and in which a rotational chamber (20) with a circular peripheral wall (22) and an axial outlet (24) is joined to the guide-chamber (18) in a radial direction.